Campaign volunteers have been calling and texting registered voters for months now, urging them to vote and making sure they have plans to get to their polling locations. This year, a new app from the progressive nonprofit New Data Project has tried to make that usual get-out-the-vote effort a little more personal by encouraging users to harass their friends—not just strangers on a phone-banking list—about voting.

The efficacy of Vote With Me, an app Hillary Clinton promoted to her 4 million Instagram followers on Monday, lies in its capacity to humiliate. Users sync their phone’s contacts with the app, which uses names and phone numbers to match entries with voter registration records. The result is a list of friends, family members, and long-lost acquaintances sorted by party identification, residence in a district with a tight race, and voting history. Vote With Me claims this information will help you nudge friends in swing districts to vote, but it’s a much more intuitive tool for shaming and snooping. If a neighbor who’s always sharing #resistance memes didn’t vote in the 2016 election, or if a college friend who helped you canvas for Barack Obama has since registered as a Republican, now you’ll know.

Or, at least, you’ll think you know. The data is only as good as public voting records, which don’t always follow voters from state to state. When I opened the app, it looked like one colleague of mine hadn’t voted since 2008—but it showed his registration state as Pennsylvania, and he’s now registered in D.C. The app didn’t surface any of the times he’s voted since he moved here. People with common names may find themselves identified as someone completely different in the app, too. There are prompts in the app that can help you find the registered voter you’re looking for, but before you text your cousin in Ohio to berate him for sitting out the 2016 election, consider that the information you’re looking at might be incomplete.

Depending on your political interest level, you may be having one of two reactions to an app that’s telling people whether their friends voted in previous elections. The first: Aren’t voting records private?! The short answer is no. Voter registration information—names, addresses, party registration, and sometimes phone numbers and email addresses—is public, as are records of whether any given person voted in any given election. The only thing that’s private is who voters picked on their respective ballots, including whether they left any slots blank. You might also be wondering why people need an app to tell them something that’s already public information. Well, it’s not that easy to look this stuff up. There’s no nationwide online search database, and you can’t simply phone city hall to see who in your grad school study group is registered with what party. Every state is different, but obtaining voting records often involves a public request for information, tens of thousands of dollars for an entire state’s records (which is sometimes the only option), and a gigantic, complex file that includes data on every registered voter in the state or county. It would be a prohibitively large investment to satisfy the curiosity of someone who isn’t running a political campaign.

In that regard, Vote With Me is a pretty revolutionary tool, in that it makes public but difficult-to-access information available to anyone with the patience to navigate a few taps and swipes. It could be particularly useful to small-time activists or citizen journalists who can get their hands on the phone numbers of local firebrands or family members of politicians but aren’t willing or able to go through the whole public-request rigmarole. (Remember when Ivanka and Eric Trump forgot to register to vote in New York in time for their dad’s big primary?) It’s also a smart marrying of two election-season conventions: interpersonal nagging (everyday people reminding friends to vote) and large-scale nagging (campaigns using data to target inconsistent voters in their own party). One 2006 study found that people who received a get-out-the-vote mailer that reminded them of their voting record—including lapses therein—were slightly more likely to vote than those who got a mailer with a general note of encouragement. But that was a judgment-free missive from a faceless organization, not a shaming text from a friend. Vote With Me is full of useful information. If only it weren’t too unreliable—and creepy—to work.

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